标题： 凯克光谱学对莱曼断裂星系及其对z>6紫外连续谱和Ly_alpha光度函数的影响 显示英文标题

标题： Keck Spectroscopy of Lyman-break Galaxies and its Implications for the UV-continuum and Ly_alpha Luminosity Functions at z>6

摘要： 我们展示了对 Subaru 深场 (SDF) 中 z>6 Lyman-break 星系 (LBG) 候选体的 Keck 光谱观测。 这些候选体是从超深的 SDF z' 波段图像中选择的 i'-dropout 物体，达到 z'=27 AB 等级。 通过 Keck 光谱观测，我们在 6< z < 6.4 范围内识别出 19 个具有显著 Ly_alpha 发射线的 LBG。 Ly_alpha 静止框架等值宽度 (EWs) 的中位数约为 50 A，其中有四个 EWs 大于 100 A。 这个定义明确的光谱样本涵盖了 -21.8< M_{紫外线}<-19.5 (0.6~5 L*_{紫外线}) 的紫外连续谱光度范围和 (0.3~3) x 10^{43}erg s^{-1}(0.3~3 L*_ {Ly_alpha}) 的 Ly_alpha 光度范围。 在修正样本不完整性后，我们从样本中推导出 <z>~6.2 处的紫外和 Ly_alpha 光度函数 (LFs)。 我们发现，我们的紫外 LF 测量结果与基于光度 LBG 样本在 5<z<7 范围内的先前研究结果一致。 我们的 Ly_alpha LF 也与在 z~5.7 和 6.6 处的 Ly_alpha 发射体调查结果总体一致。 这项研究显示，对 LBG 的深度光谱观测可以为 z>6 处的紫外和 Ly_alpha LFs 提供独特的约束。 显示英文摘要

摘要： We present Keck spectroscopic observations of z>6 Lyman-break galaxy (LBG) candidates in the Subaru Deep Field (SDF). The candidates were selected as i'-dropout objects down to z'=27 AB magnitudes from an ultra-deep SDF z'-band image. With the Keck spectroscopy we identified 19 LBGs with prominent Ly_alpha emission lines at 6< z < 6.4. The median value of the Ly_alpha rest-frame equivalent widths (EWs) is ~50 A, with four EWs >100 A. This well-defined spectroscopic sample spans a UV-continuum luminosity range of -21.8< M_{UV}<-19.5 (0.6~5 L*_{UV}) and a Ly_alpha luminosity range of (0.3~3) x 10^{43} erg s^{-1} (0.3~3 L*_ {Ly_alpha}). We derive the UV and Ly_alpha luminosity functions (LFs) from our sample at <z>~6.2 after we correct for sample incompleteness. We find that our measurement of the UV LF is consistent with the results of previous studies based on photometric LBG samples at 5<z<7. Our Ly_alpha LF is also generally in agreement with the results of Ly_alpha-emitter surveys at z~5.7 and 6.6. This study shows that deep spectroscopic observations of LBGs can provide unique constraints on both the UV and Ly_alpha LFs at z>6.